Hi, Professional
I would like to get the answer and solution with this detail.
My customer using VVR 3.3 on windows 2003 and all service all fine but there are lag of blocks change between primary and second but I'm new in this product and I have no idea to determine which is the main cuase of the issue, please suugest me. What can probaby occur with is system.
Thank you.
Hi mscservice,
VR has 3 modes for replication. Synchronous, Asynchronous and Synchronous-Override.
Synchronous ensures that all writes are commited to all secondaries and the primary before reporting the write as successful to the Application. This means that the best I/O throughput is the link to the slowest secondary. This mode will not allow writes to be done if the secondaries are not available.
Asynchronous relies on the replicator log to buffer the writes to be sent to the secondaries. In this mode, writes are reported as successful once they are commited to the replicator log and to the disks at the primary site. Writes are sent to the secondaries as bandwidth permits. This means that the secondaries are typicaly behind the primary during heavy I/O periods.
Synchronous-override is a combination of the synchronous and asynchronous. Basically, this mode will act as synchronous most of the time. However, if there is a network outage then replication switches to asynchronous automatically to prevent stopage of I/O.
I would guess that your running in Asynchronous or Synchronous-Override mode.
Please let us know if this helps.
Thank you,
Wally
